Field
Exemplary embodiments of the present disclosure relate to an apparatus and method to manufacture glass sheet, and to fusion down draw apparatus and method to manufacture glass sheet.
Discussion of the Background
Recently, interest in fusion down draw as a method of manufacturing glass sheets has been receiving increasing interest. The fusion down draw glass manufacturing may include a lower pull roll apparatus having a master motor to rotate a lower pair of rolls at a constant angular velocity and an upper pull roll apparatus with upper slave motors configured to rotate an upper pair of rolls at torques that match a predetermined percentage of the measured torque of the master motor of the lower pair of rolls.
As described in co-pending U.S. patent application Ser. No. 13/305,810, filed Nov. 29, 2011, the entire contents of which hereby are incorporated by reference as if fully set forth herein, the master/slave configuration of the lower/upper pull roll apparatus can be beneficial under various process applications.
Further, the fusion down draw glass manufacturing process may include a control device configured to independently operate the upper pull roll apparatus and the lower pull roll apparatus such that the upper pair of draw rolls rotates with a substantially constant torque and the lower pair of draw rolls rotates with a substantially constant angular velocity.
As glass sheet requirements become more demanding, capabilities of these pull roll apparatuses may be exceeded.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form any part of the prior art nor what the prior art may suggest to a person of ordinary skill in the art.